From roughly the 1820s onwards, European societies accumulated masses of statistics about the conditions and activities of their societies. In the succeeding several decades, social statistics was effectively institutionalized, and a distinctive social-statistical reasoning (quite different from the earlier political arithmetic) quickly took shape. The great accomplishment of the early social statisticians was to make familiar for the first time the notion of a population, or system, which produces large-scale regularities imperceptible at the level of its constituent individuals. In the eighteenth century only births and deaths had seemed law-like in the aggregate; in the early nineteenth century, by contrast, statisticians began to perceive a whole new array of apparent "laws of social life." My aim is to reconstruct the distinctive contributions of medicine to the early social statistics. It is well known that physicians were preeminent among early social statisticians, and that the medical tradition of social observation fed in directly to inform statistical investigations. But it is less well understood how medicine contributed to the conceptual development of social statistics. This is the focus of my research. It is important to remember that the early work of social statisticians long preceded the mathematical innovations of the late nineteenth century which created modern statistics; accordingly reconstructing the conceptual foundations of early social statistics means asking how categories and classifications were laid down; what it meant to think statistically; and how regularities and apparent "laws of social life" should be interpreted. By reexamining the play of medical notions in social statistics I hope to open a new way of seeing the history of social medicine, and throw new light on some of the links between medicine and the emergence of the social sciences in the nineteenth century. My research involves a close analysis of a limited number of printed and archival sources. Since I have already done substantial spade-work on the project, it seems to me feasible to complete it in two years.